Much of what you need to pay attention to for installing carpet tile is the same as when doing resilient floor tile - substrate preparation, moisture testing, adhesive selection and job layout.
Adhesives for carpet tile are varied as are the methods for applying them. In his December 2008 FCI article, “Acrylic Adhesive Basics,” Wally Giambastiani said it best:
The adhesives used for carpet tile installations are acrylic-based adhesives - these adhesives remain tacky after they dry which allows for the “releasable installation” of the carpet tile and are developed to have a low peel strength (easily pulled off the floor) and high shear strength (hold the tile from sliding). After installation, you can easily pull up the tile and replace with new tile. During installation, and for this releasable feature to work properly, you must allow the adhesive to dry to the touch prior to installing the carpet tile (otherwise this becomes a permanent or non-release installation). Please note that there are different pressure sensitive adhesives – it is your responsibility to know the type of carpet, carpet backing, and under what conditions the carpet is going to be installed and used.
Wally also covered the importance of knowing what type of traffic conditions, environmental conditions and substrate conditions will be present before deciding what type of adhesive to use to install carpet tile. Once you have this information through job site inspection, you’ll be able to determine how much floor prep is necessary and make the decision on which adhesive to use.
It is critical to use the right trowel when you go this route. Carpet tile, like many resilient floors, is usually installed with a very thin bed of adhesive so too much can be a bad thing. Less is better in most cases. One of the advantages to using a trowel is that any debris or high spots in the floor can be observed as the trowel crosses the substrate and immediately corrected. For a spray- or roller-applied adhesive, this feature is not present so it is absolutely critical to carefully look at the floor to see if there are any defects in the substrate. One way to do this is to lightly pass a scraper across the floor. Then, before starting with the adhesive you have to sweep and/or vacuum the floor and do it again before the adhesive is applied. Take extra care to make sure the floor is flat and clean when you are using “non-trowel-applied” adhesives.
Laying out carpet tile is not that different from resilient floor tile. Lay out the areas carefully and center the room as best you can to avoid border tiles that are less than six inches or so. Before spreading adhesive it is important to dry lay some of the tile because many carpet tile patterns are directional - and you will see arrows on the back of the tile. If the tile is patterned, the designer or the owner may want it laid a particular way - either all in one direction or quarter turned. Even non-patterned tile has a direction and if a “seamless’ look is preferred then all the tiles need to be installed the same way. However, quarter turning these tiles gives a totally different look. There really is no right way or wrong way except that someone may have a preference, so it’s better to know this before you start. There also are a lot of applications where carpet tile is being used in patterns, borders, flash coving and other custom work and since many resilient installers have experience in this type of work, this presents an opportunity to show off your talent in a new material. But lay it out before you start and make sure that what you have in mind is the same as the owner or designer who chose the material.
The actual installation of carpet tiles needs to be snug up against any walls or fixtures, especially with “loose lay” or “self adhesive” tiles. I inspected a job last year that had major gaps in the tile in some areas. When I looked under the baseboards I found that the tile was tight up against the wall. However, it was not installed that way! The installer left a gap around the edges and the tile shifted once it was exposed to traffic. I had this same experience in my own office when I installed carpet tile. Because of some pending construction I was not able to finish the floor right up to one wall and sure enough the tile “walked,” creating little gaps that I periodically adjust. Luckily the construction is getting done this spring so I will get this job done at last. What is that old saying about the shoemaker whose children don’t have shoes?
I think the growing popularity of carpet tile presents a challenge for installers to put to good use what they know abut the very challenging and technical field of resilient floor installation. It’s a world of opportunity for more work and more ways to show off their craftsmanship.